It is becoming more important to be able to provide telecommunication services to fixed and mobile subscribers as efficient and inexpensively as possible. Further, the increased use of mobile applications has resulted in much focus on developing wireless systems capable of delivering large amounts of data at high speed.
Currently, as part of the Proximity Services (ProSe) capability introduced in Release 13 of the LTE Standards, a basic level of functionality has been described to allow network-to-user equipment (UE) relaying, specifically targeting Public Safety use cases. This functionality relies on the reuse of a sidelink radio communication channel between devices to route traffic at the Internet Protocol (IP) layer. The following functions are supported using this relaying approach:                Unicast relaying: Based on one-to-one direct communication between a Remote UE, that is not served by the Evolved Universal Terrestrial Access Network (E-UTRAN), including support for the relaying of unicast traffic (uplink and downlink) between Remote UEs and the E-UTRAN. The ProSe UE-to-Network Relay provides a generic layer 3 (L3) forwarding function that may relay any type of IP traffic that is relevant for public safety communication.        Evolved Multimedia Broadcast Multicast Service (eMBMS) relay support: One to many communication, including support for the relaying of eMBMS to Remote UEs served by the UE-to-NW Relay.        E-UTRAN Cell Global Identifier (ECGI) announcement: The announcement of the ECGI by a ProSe UE-to-NW Relay allowing remote UEs served by a ProSe UE-to-NW Relay to receive the value of the ECGI of the cell serving the ProSe UE-to-NW Relay.        
The application of relaying using the sidelink channel to more general use cases, beyond the requirements of Public Security, may require modifications to be made to the currently provided relaying functionality.